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How to create a *limited* in-memory SQLite database

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Message        tseyfarth          Post subject: How to create a *limited* 
in-memory SQLite databasePosted: Sun Mar 31, 2013 7:43 pm                       
  
Joined: Sat Dec 04, 2010 9:14 pm
Posts: 876                Hello all,

Can anyone tell me how to create an in-memory SQLite database.  I would like to 
limit it to only certain tables, since the whole db is not necessary. Basically 
tables that hold configuration data.  I am a bit skittish to do this with 
tables that need data written to them, since there is an opportunity to loose 
data - for many reasons!

Thank you,
Tim   
                             Top                npalardy          Post subject: 
Re: How to create a *limited* in-memory SQLite databasePosted: Sun Mar 31, 2013 
8:52 pm                       Real Software Engineer          
Joined: Sat Dec 24, 2005 8:18 pm
Posts: 7771
Location: Canada, Alberta, Near Red Deer                tseyfarth wrote:Hello 
all,

Can anyone tell me how to create an in-memory SQLite database.  I would like to 
limit it to only certain tables, since the whole db is not necessary. Basically 
tables that hold configuration data.  I am a bit skittish to do this with 
tables that need data written to them, since there is an opportunity to loose 
data - for many reasons!

Thank you,
Tim

An in memory database would disappear every time the program was shut down
Not sure that's what you want ?      
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                             Top                tseyfarth          Post 
subject: Re: How to create a *limited* in-memory SQLite databasePosted: Sun Mar 
31, 2013 9:03 pm                         
Joined: Sat Dec 04, 2010 9:14 pm
Posts: 876                Hello npalardy,

The in memory would be a copy of the certain tables that are used frequently 
during the executiion of the application.  It would serve the purpose of having 
the data available to many objects, but without creating individual properties 
or local variables for each of them.  I *think* it would be faster and more 
convenient than having several copies of the tables open in various objects - 
not sure about which is better either however.

The loss of the data on app shutdown is why I would only utilize "read" data, 
that contains app config data.  On app start, it would read and load that data 
into memory for use by any object that requires it within the application.

Tim   
                             Top                HMARROQUINC          Post 
subject: Re: How to create a *limited* in-memory SQLite databasePosted: Sun Mar 
31, 2013 10:53 pm                                 
Joined: Sun Jan 25, 2009 5:11 pm
Posts: 546
Location: Guatemala, Central America                Something like this:

dim db as new REALSQLDatabase

if db.Connect = false then
  MsgBox "Failed to create the database "
  exit
end if

// Now you got yourself an in-memory database, create the tables
dim s as string
s = "Create table Test1(id integer primary key, field1 text, field2  text)"
db.SQLExecute(s)
if db.Error then
  MsgBox "Error creating the database " + EndOfLine + _
  CStr(db.ErrorCode) + " - " + db.ErrorMessage
end if

// Now fill table with some data
dim rec as DatabaseRecord
dim i as integer
for i = 1 to 10
  rec = new DatabaseRecord
  rec.Column("field1") = "Test " + CStr(i)
  rec.Column("field2") = "Something here"
  db.InsertRecord("Test1", rec)
  if db.error then
  MsgBox "Error inserting the record" + EndOfLine + _
  CStr(db.ErrorCode) + " - " + db.ErrorMessage
  exit
  end if
next i
      
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                             Top                timhare          Post subject: 
Re: How to create a *limited* in-memory SQLite databasePosted: Mon Apr 01, 2013 
2:15 am                         
Joined: Fri Jan 06, 2006 3:21 pm
Posts: 12188
Location: Portland, OR  USA                For config info, I use a Dictionary. 
 I have a db table of name/value pairs that I read into a dictionary on app 
startup and write back out on app exit.  It's much more convenient than an 
in-memory database.  If your config data can be represented as name/value 
pairs, I would highly recommend the dictionary approach.  Use method 
overloading on some getter/setter methods to make it really convenient - no 
explicit data conversions required.

dim s as string = configvalue("name")
dim i as integer = configvalue("count")
dim d as date = configvalue("lastrun")   
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